In medieval times the word incubus meant an evil demon that was supposed to have sexual intercourse with women during their sleep. There was also a female equivalent called the succubus. The word is derived from the Latin incubo meaning "nightmare". Incubus has since been extended to cover anything that is a nightmare, or that weighs heavily upon the mind.
Sodom and Gomorrah
The story of Sodom and Gomorrah is chronicled in Genesis and describes two cities that had been ravaged by warfare. Two angels descended on Lot; a resident of Sodom, to warn that God was displeased with the sin that was overrunning the city. An angry mob demanded that Lot introduce them to the Angels. Suspicious of their intent, he offered his two daughters to the mob. They refused and Lot and his family fled the city which was destroyed. Unfortunately Lot's wife looked back and was turned into a pillar of salt. Sodom and Gomorrah has since become a term to describe sin and depravity.
Black's reference to "too many Ovaltines" refers to the malt-flavoured beverage invented by Swiss chemist Dr Wander in 1904. The drink became so popular that it spawned a radio show,
featuring a cast of singing children, called the Ovaltinies in 1935. Ten million jars of Ovaltine are still sold in the UK every year.
Going to the zoo
Julie Felix's song Daddy's Taking Us To The Zoo was released as a single in 1969 and has since become a children's favourite. Julie is a singer and protest songwriter who was famous in the 1960's for her appearances on The Frost Report and for her hosting her own show.
The animal rights protestors Jamie and Zoe are named after two of the travelling companions from Doctor Who. Jamie McCrimmon, made his debut in the 1966 story The Highlanders, while Zoe Heriot first appeared in the 1968 story The Wheel in Space. Patrick Troughton was the Doctor.
There are no prizes for guessing the inspiration for the book Jude reads to Joey, William Watkins and the Academy of Wizards' by AGL Stuart. Could the author be referring to a certain Brigadier from Doctor Who, one Alistair Gordon Lethbridge-Stewart?
Rabies is a virus spread by the saliva of infected animals and is transmitted to pets and humans by bites, or by contamination of an open cut. Untreated, rabies can cause death.
Tetanus (commonly called lockjaw) occurs when a wound becomes infected with bacterial spores of Clostridium tetani. The spores germinate and multiply to produce a powerful poison, which greatly affects the muscles.
Spread by rodents, the Bubonic Plague causes a painful swelling of the lymph glands called buboes. The disease causes red spots on the skin, which then turns black. The plague was brought by trade ships in 1348 and soon moved to the North of England, where it became known as The Black Death. Within five years 25 million people - a third of the population of Europe - had been killed.
Friends of the Earth
Friends of the Earth was founded in San Francisco in 1969 by David Brower to create a more healthy, just world. The organisation was the first to bring to the public's attention the impact of the rain forest loss on the regulation of world climate and atmosphere.